One of the effects of recoil is muzzle climb. Muzzle climb is a factor in timed rapid fire. Higher rise increases the time required to realign the sights with the target and also causes inaccuracy by moving the firearm off target during the bullet travel down the barrel.
There are many devices that seek to reduce recoil. Common names include muzzle brakes, recoil compensators, suppressors, and linear compensators. Many devices function by trapping the propellant gases at the muzzle, or beyond with an attachment, and guiding the gases upward in an attempt to reduce the effect of muzzle climb. Some also vent to the side with a backward angle.
One technique takes gases from near the chamber-barrel rifling interface, carries them separate from the rifled portion of the barrel to the muzzle, then vents them directly upward. One technique involves directly porting a shotgun barrel near the muzzle. Some of these foul after relatively few rounds have been fired and must be cleaned to restore functionality. Some direct gases back toward the shooter or adjacent people. Many allow the firearm to move significantly off target, requiring significant movement of the firearm to re-acquire the target. There is a need for a recoil reduction system which reduces muzzle climb so that accuracy is improved and that subsequent shots may be fired more quickly.
Muzzle brakes and compensators work at the muzzle end of a firearm. Some such as U.S. Pat. No. 4,545,285 by McLain direct gases upward and rearward, towards a shooter. Others, such as U.S. Pat. No. 7,059,235 by Hanslick direct gases upward and forward, away from a shooter.
A variation on this technique is taught in U.S. Pat. No. 6,595,099 by Olsen et al. This teaching reveals trapping the propellant gases at the muzzle, or beyond with an attachment, and guiding the gases through multiports upward in an attempt to reduce the effect of muzzle climb. Some of the multiports also vent to the side with a backward angle to reduce recoil.
Another technique ports the barrel back away from the muzzle. This is shown in U.S. Pat. No. 4,942,801, 5,123,328 & 5,423,242 by Schuemann These teach that the center of a plurality of ports is approximately midway between the muzzle and the chamber and located along the top of the barrel, pointed upwardly.
A variation on this technique is taught in U.S. Pat. No. 6,769,346 by Rosenthal. This teaches taking gases from near the bottom of the barrel and porting them through a passage to vent them in an upward direction.
The farther from the chamber that the gasses are tapped, the longer the firearm has had to recoil and have muzzle climb. Tapping the gasses just before they leave the muzzle only operates as the bullet is almost leaving the barrel and after muzzle rise and recoil has begun. Techniques that vent gasses upward from the top of the barrel make using a top mounted scope difficult or impossible. Rear venting techniques can cause gasses to interfere with the shooter or adjacent people. What is needed is a firearm that begins to address recoil and muzzle climb very soon after the bullet has begun traveling, vents the gasses away from the shooter and those nearby, does not require frequent cleaning, and allows for a top mounted scope to be installed.